CN115217848A

CN115217848A - Magnetic suspension bearing system and control method thereof

Info

Publication number: CN115217848A
Application number: CN202210869392.XA
Authority: CN
Inventors: 王举; 龚高; 张超; 魏志韬; 邓艳
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2022-07-21
Filing date: 2022-07-21
Publication date: 2022-10-21

Abstract

The invention provides a magnetic suspension bearing system and a control method thereof, wherein the magnetic suspension bearing system comprises: the axial magnetic bearing and the radial magnetic bearing are sleeved on the periphery of the rotating shaft, the axial magnetic bearing comprises an axial magnetic bearing stator, the radial magnetic bearing comprises a radial magnetic bearing stator and a radial magnetic bearing rotor, the radial magnetic bearing rotor is sleeved on the periphery of the rotating shaft and can rotate together, the radial magnetic bearing stator is positioned on the periphery of the radial magnetic bearing rotor and can apply radial electromagnetic force to the radial magnetic bearing rotor, at least part of structure of the axial magnetic bearing stator is positioned at one axial end of the radial magnetic bearing rotor, and the axial magnetic bearing stator can apply axial electromagnetic force to the radial magnetic bearing rotor. According to the invention, the radial magnetic bearing and the axial magnetic bearing are effectively combined together to form an integrated magnetic bearing structure with a shaft and a radial, so that the axial size of the rotor is reduced, and the problem of low rotor fixed frequency deviation is solved.

Description

Magnetic suspension bearing system and control method thereof

Technical Field

The invention relates to the technical field of magnetic suspension, in particular to a magnetic suspension bearing system and a control method thereof.

Background

The magnetic suspension bearing has the characteristics of no mechanical friction, no lubrication, high critical rotating speed, long service life, high reliability and the like, and is widely applied to the fields of high rotating speed, ultrahigh rotating speed and the like. The displacement sensor is an important component of a magnetic suspension system. The magnetic suspension sensor and the bearing are reasonably arranged, so that the reliability and the stability of the magnetic suspension system can be improved.

Referring to fig. 1, a conventional magnetic suspension bearing system generally adopts a sensing-actuated separation mode. As shown in the prior art, the basic structure of the axial displacement sensor comprises a rotating shaft 1', a radial displacement sensor 2', a radial bearing 3', a motor rotor 4', an axial bearing iron core 5', an axial bearing coil 6', a rotor thrust disc 7 'and an axial displacement sensor 8'.

The axial bearing stators are arranged on two sides of the rotor thrust disc 7', the radial displacement sensor 2' for detecting the radial displacement of the rotor is arranged on one side of the radial bearing 3', the axial displacement sensor 8' for detecting the axial displacement of the rotor is arranged on the left end surface of the rotating shaft 1', and the sensors and the bearings are separately installed. When the rotating shaft 1' is displaced radially or axially, the sensor converts the detected displacement change into a signal and transmits the signal to the system, and further the bearing output is controlled to enable the shaft to return to a safe position.

This structure has the following disadvantages:

1. the thrust bearing 7 'occupies a certain length of the rotating shaft 1', so that the axial size of the rotor is long, and the problem of low solid-phase frequency deviation of the rotor is easy to occur

2. The detected value of the axial sensor may not be consistent with the actual axial clearance data of the thrust bearing (mainly because the stable rise of the optical axis in the running process of the motor can generate thermal expansion, the data detected by the axial displacement sensor 8 is actually the axial offset of the rotor 1' and the axial expansion of the rotating shaft, so that errors or mistakes exist), and the control precision of the system can be influenced;

3. the sensors and the axial bearings are arranged separately, so that the number of outlet terminals of the whole system is large;

4. the arrangement of the axial sensor needs to occupy a certain axial space of the rotating shaft, so that the length of the rotating shaft is increased, the dynamic performance of the rotating shaft is reduced, and the cost of the whole system is increased.

As shown in fig. 2, patent No. CN110242670A discloses a magnetic suspension bearing system and a tool having the same, the magnetic suspension bearing system includes: the shaft 10', the thrust bearing 20', the first axial core assembly 30', the second axial core assembly 40', and the inspection assembly 50'. Wherein the first axial core assembly 30' is sleeved on the rotating shaft 10' and is positioned at a first side of the thrust bearing 20 '; the second axial iron core 40' is sleeved on the rotating shaft 10' and is positioned at the second side of the thrust bearing 20 '; the detection assembly 50' is integrated on either the first axial core assembly 30' or the second axial core assembly 40 '. This magnetic suspension bearing system is integrated on first bearing iron assembly or second axial iron core subassembly with the determine module, can improve its magnetic suspension bearing system's control accuracy to can reduce the length of pivot, and then can improve the mechanical properties and the quality of pivot. The structure has the following defects: the thrust bearing 20' occupies a certain length of the shaft 10', and the detection assembly 50' integrated only on the first axial core assembly 30' or the second axial core assembly 40' cannot determine the rotor heating elongation.

Because the thrust bearing of the magnetic suspension bearing system in the prior art occupies a certain length of the rotating shaft, the axial size of the rotor is long, the technical problems of low fixed frequency of the rotor and the like are easy to occur, and the invention researches and designs the magnetic suspension bearing system and the control method thereof.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the defects that the thrust bearing of the magnetic suspension bearing system in the prior art occupies a certain length of a rotating shaft, so that the axial size of a rotor is long, and the solid frequency deviation of the rotor is easy to occur, thereby providing the magnetic suspension bearing system and the control method thereof.

In order to solve the above problems, the present invention provides a magnetic bearing system, comprising:

the magnetic bearing comprises a rotating shaft, an axial magnetic bearing and a radial magnetic bearing, wherein the axial magnetic bearing and the radial magnetic bearing are sleeved on the periphery of the rotating shaft, the axial magnetic bearing comprises an axial magnetic bearing stator, the radial magnetic bearing comprises a radial magnetic bearing stator and a radial magnetic bearing rotor, the radial magnetic bearing rotor is sleeved on the periphery of the rotating shaft and can rotate along with the rotating shaft, the radial magnetic bearing stator is positioned on the periphery of the radial magnetic bearing rotor and can apply radial electromagnetic force to the radial magnetic bearing rotor, at least part of the structure of the axial magnetic bearing stator is positioned at one axial end of the radial magnetic bearing rotor along the axial direction of the rotating shaft, and the axial magnetic bearing stator can apply axial electromagnetic force to the radial magnetic bearing rotor.

In some embodiments, the axial magnetic bearing stator includes an axial magnetic bearing core and an axial magnetic bearing coil, the axial magnetic bearing core includes a main body portion, a first annular portion and a second annular portion, the main body portion is a disc structure having a central hole, the central hole accommodates the rotating shaft therethrough, one end of the first annular portion is connected to a radial inner end of the main body portion and the other end extends in a direction of the radial magnetic bearing rotor, one end of the second annular portion is connected to the main body portion and the other end extends in a direction of the radial magnetic bearing rotor, the second annular portion is located radially outside the first annular portion to form a receiving groove between a radially outside of the first annular portion and a radially inside of the second annular portion, and the axial magnetic bearing coil is disposed in the receiving groove and wound around an outer periphery of the first annular portion.

In some embodiments, the first annular portion extends in an axial direction of the rotating shaft and is spaced a first predetermined distance from the radial magnetic bearing rotor, and the second annular portion also extends in the axial direction of the rotating shaft and is spaced a second predetermined distance from the radial magnetic bearing rotor.

In some embodiments, the radial magnetic bearing further comprises a radial magnetic bearing rotor baffle sleeved on the rotating shaft, and the radial magnetic bearing rotor baffle has two, wherein one radial magnetic bearing rotor baffle is located at one axial end of the radial magnetic bearing rotor, and the other radial magnetic bearing rotor baffle is located at the other axial end of the radial magnetic bearing rotor; the two radial magnetic bearing rotor baffles are fixedly connected with the radial magnetic bearing rotor and can integrally rotate along with the radial magnetic bearing rotor.

In some embodiments, the radial magnetic bearing rotor baffles of the two radial magnetic bearing rotor baffles that are relatively close to the first and second annular portions are spaced a third predetermined distance from both the first and second annular portions.

In some embodiments, the radial magnetic bearing stator includes a radial magnetic bearing stator core, which is also an annular structure, sleeved around a radial outer periphery of the radial magnetic bearing rotor and spaced apart from the radial magnetic bearing rotor, and a radial magnetic bearing coil.

In some embodiments, the axial magnetic bearing core further includes a third annular portion having one end connected to the radially outer end of the main body portion and another end extending radially outward of and connected to the radial magnetic bearing stator core.

In some embodiments, the magnetic bearing further comprises a casing, the casing is a cylindrical structure and is located at the outer peripheries of the axial magnetic bearing and the radial magnetic bearing, one end of the third annular portion is located at one axial side of the radial magnetic bearing, and the other end of the third annular portion is located at the other axial side of the radial magnetic bearing, so that part of the structure of the third annular portion is located at the radial outer periphery of the radial magnetic bearing core, the radial inner periphery of the third annular portion is fixedly connected with the radial magnetic bearing stator core, and the radial outer periphery of the third annular portion is fixedly connected with the casing.

In some embodiments, the magnetic bearing further comprises an axial displacement sensor and an axial displacement detector, the axial displacement sensor is disposed on the axial magnetic bearing, the axial displacement detector is disposed on the rotating shaft and can move along with the movement of the rotating shaft, and the axial displacement sensor can detect the axial movement of the axial displacement detector.

In some embodiments, when the axial magnetic bearing stator includes an axial magnetic bearing core, the axial displacement sensor is of an annular structure and is fixedly disposed on the axial magnetic bearing core, the axial displacement detector is also of an annular structure and is fixedly disposed on the rotating shaft, and the axial displacement detector is further capable of oil-blocking the axial magnetic bearing and the radial magnetic bearing.

In some embodiments, the magnetic bearing assembly comprises at least two magnetic bearing assemblies, one of the magnetic bearing assemblies is disposed on one axial side of the motor assembly, the other magnetic bearing assembly is disposed on the other axial side of the motor assembly, and the two magnetic bearing assemblies are symmetrically disposed relative to the motor assembly.

In some embodiments, the motor assembly includes a motor rotor and a motor stator.

In some embodiments, the axial displacement sensor is capable of detecting axial displacement of the axial displacement detector, and the cooling device is capable of passing a cooling fluid to cool the rotating shaft, the axial magnetic bearing and the radial magnetic bearing according to the axial displacement data detected by the axial displacement sensor.

The invention also provides a method of controlling a magnetic bearing system as claimed in any of the preceding claims, wherein: when the axial magnetic bearing stator comprises an axial magnetic bearing core and axial magnetic bearing coils, and when the magnetic bearing system further comprises a cooling device:

the control method comprises the following steps:

detecting, namely detecting the axial deviation condition of the rotating shaft through an axial displacement sensor on one axial side of the motor component, and simultaneously detecting the axial deviation condition of the rotating shaft through an axial displacement sensor on the other axial side of the motor component;

judging whether the rotating shaft operates in a standard temperature interval or a non-standard temperature interval according to the axial deviation condition detected by the axial displacement sensors on the two axial sides of the motor assembly;

a control step of controlling the energizing current of an axial magnetic bearing coil of the axial magnetic bearing to change to adjust the axial deviation of the rotating shaft when the rotating shaft operates in a standard temperature interval, and turning off the cooling device at the moment; when the rotating shaft operates in a non-standard temperature interval, controlling the cooling device to be opened to cool the rotating shaft, simultaneously controlling an axial magnetic bearing coil of the axial magnetic bearing to operate, and controlling the energizing current of the axial magnetic bearing coil to be changed or unchanged;

the standard temperature interval is a temperature interval in which the rotating shaft does not deform due to expansion with heat and contraction with cold, and the non-standard temperature interval is a temperature interval in which the rotating shaft deforms due to expansion with heat and contraction with cold.

In some embodiments, in the detecting step, a first gap between the axial displacement detecting member and the corresponding axial displacement detecting member is detected by an axial displacement sensor on one axial side of the motor assembly, and a second gap between the axial displacement detecting member and the corresponding axial displacement detecting member is detected by an axial displacement sensor on the other axial side of the motor assembly;

in the judging step, when the first gap is decreased and the second gap is increased, and the decrease amount of the first gap and the increase amount of the second gap are within an error range; or, when the first gap is increased and the second gap is decreased, and the amount of increase of the first gap and the amount of decrease of the second gap are within an error range; judging that the rotating shaft operates in a standard temperature range;

when the first gap is decreased and the second gap is increased, and the decrease amount of the first gap and the increase amount of the second gap are not within an error range; or, when the first gap is increased and the second gap is decreased, and the amount of increase of the first gap and the amount of decrease of the second gap are not within an error range; or when the first gap and the second gap are simultaneously reduced or simultaneously increased, judging that the rotating shaft operates in a non-standard temperature range;

in the control step, when the rotating shaft operates in a standard temperature interval, the energizing current of an axial magnetic bearing coil of the axial magnetic bearing is controlled to change so as to adjust the first gap and the second gap, and at the moment, the cooling device is closed; when the rotating shaft operates in a non-standard temperature interval, controlling the cooling device to be opened so as to cool the rotating shaft, and simultaneously controlling an axial magnetic bearing coil of the axial magnetic bearing to operate and controlling the energizing current of the axial magnetic bearing coil to be changed or unchanged; and controlling the increase or decrease of the cooling flow rate of the cooling device according to the first gap and the second gap.

The magnetic suspension bearing system and the control method thereof provided by the invention have the following beneficial effects:

1. the invention makes the radial magnetic bearing stator located at the periphery of the radial magnetic bearing rotor and can apply radial electromagnetic force to the radial magnetic bearing rotor through the effective arrangement of the axial magnetic bearing and the radial magnetic bearing, at least part of the structure of the axial magnetic bearing stator is located at one axial end of the radial magnetic bearing rotor, the axial magnetic bearing stator can apply axial electromagnetic force to the radial magnetic bearing rotor, so that the radial magnetic bearing rotor can be applied with radial electromagnetic force by the radial magnetic bearing stator to adjust the radial offset of the rotating shaft, and simultaneously, the axial magnetic bearing rotor can be applied with axial electromagnetic force by the axial magnetic bearing stator to adjust the axial offset of the rotating shaft, and finally, the purpose of realizing radial and axial support to the rotating shaft is achieved; at the moment, the radial magnetic bearing rotor can be respectively subjected to forces in the radial direction, the lower direction, the left direction and the right direction, which are applied by the radial magnetic bearing stator, and can be subjected to forces in the axial direction, which are applied by the axial magnetic bearing stator, so that the magnetic suspension bearing (the radial magnetic bearing rotor) is formed into a magnetic suspension bearing with 5 degrees of freedom, the use of parts is reduced, the axial size of the rotor is shortened, and the fixed frequency of the rotor is improved;

2. the invention also improves the universality of bearing parts and avoids the processing of two sets of drawings of front and rear axial parts by at least two magnetic bearing components, wherein one magnetic bearing component is arranged at one axial side of the motor component, the other magnetic bearing component is arranged at the other axial side of the motor component, and the two magnetic bearing components are symmetrically arranged relative to the motor component; in addition, as the axial sensor structures are arranged on the two sides of the front axial bearing and the rear axial bearing, under the condition that the rotor generates heat, the axial position of the rotor is calculated in a differential mode, and the rotor is judged and adjusted to be positioned at the central position, so that the condition that the rotor is axially separated from the central position due to the heating extension of the rotor is avoided, the heating extension amount of the rotor can be effectively detected, and the problem that the heating extension amount cannot be detected and determined in the prior art is solved;

3. the invention adopts the structure that the axial sensors are arranged on both sides of the front axial bearing and the rear axial bearing, the axial extension condition is determined by the axial clearance obtained by calculation through setting the axial extension when the standard temperature interval of the rotor is operated, the extension of the rotor is stabilized in a certain interval through adjusting and increasing or reducing the cooling medium introduced into the magnetic suspension bearing system, the bearing current is reduced, and the operation precision is improved. The invention avoids the flow of the cooling fluid from falling into a nonstandard temperature interval by controlling the flow of the cooling fluid according to the axial elongation, thereby avoiding the error (namely avoiding the detection error caused by axial expansion), judges whether the cooling fluid is in the standard temperature interval or the nonstandard temperature interval by difference, can effectively detect the heating elongation of the rotor, and solves the problem that the detection value of the axial sensor is possibly inconsistent with the actual axial clearance data of the thrust bearing, which can influence the control precision of the system;

4. the axial displacement sensor is arranged on the axial magnetic bearing, so that the axial displacement sensor and the axial magnetic bearing are combined into a whole, the problem that the number of outlet terminals of the whole system is large due to the fact that the conventional sensor and the axial bearing are arranged separately is effectively solved, and the problems that the length of a main shaft is increased, the dynamic performance of the main shaft is reduced and the cost of the whole system is increased due to the fact that a certain axial space is occupied when the axial sensor is arranged are solved.

Drawings

Fig. 1 is a structural view of a magnetic levitation system of background art 1;

FIG. 2 is a diagram of a magnetic levitation system of background art 2;

FIG. 3 is a block diagram of a magnetic levitation system of the present invention;

FIG. 4 is an enlarged partial structural view of the axial magnetic bearing core of FIG. 3;

fig. 5 is a flow chart of a control method of the magnetic levitation system of the present invention.

The reference numerals are represented as:

1. a rotating shaft; 100. an axial magnetic bearing; 101. an axial magnetic bearing stator; 200. a radial magnetic bearing; 201. a radial magnetic bearing stator; 2. an axial displacement detecting member; 3. an axial displacement sensor; 4. an axial magnetic bearing coil; 5. a radial magnetic bearing rotor baffle; 6. a radial magnetic bearing rotor; 7. a radial magnetic bearing stator core; 8. an axial magnetic bearing core; 80. a main body portion; 81. a first annular portion; 82. a second annular portion; 83. a third annular portion; 84. accommodating a tank; 9. a radial magnetic bearing coil; 10. a motor rotor; 11. a motor stator; 12. a housing; 13. and (6) a cooling device.

Detailed Description

As shown in fig. 3-4, the present invention provides a magnetic bearing system comprising:

the magnetic bearing comprises a rotating shaft 1 (or called the rotating shaft), an axial magnetic bearing 100 and a radial magnetic bearing 200, wherein the axial magnetic bearing 100 and the radial magnetic bearing 200 are both sleeved on the periphery of the rotating shaft 1, the axial magnetic bearing 100 comprises an axial magnetic bearing stator 101, the radial magnetic bearing 200 comprises a radial magnetic bearing stator 201 and a radial magnetic bearing rotor 6, the radial magnetic bearing rotor 6 is sleeved on the periphery of the rotating shaft 1 and can rotate along with the rotating shaft 1, the radial magnetic bearing stator 201 is positioned on the periphery of the radial magnetic bearing rotor 6 and can apply radial electromagnetic force to the radial magnetic bearing rotor 6, at least part of the structure of the axial magnetic bearing stator 101 in the axial direction of the rotating shaft 1 is positioned at one axial end of the radial magnetic bearing rotor 6, and the axial magnetic bearing stator 101 can apply axial electromagnetic force to the radial magnetic bearing rotor 6.

The invention makes the radial magnetic bearing stator located at the periphery of the radial magnetic bearing rotor and can apply radial electromagnetic force to the radial magnetic bearing rotor through the effective arrangement of the axial magnetic bearing and the radial magnetic bearing, at least part of the structure of the axial magnetic bearing stator is located at one axial end of the radial magnetic bearing rotor, the axial magnetic bearing stator can apply axial electromagnetic force to the radial magnetic bearing rotor, thereby making the radial magnetic bearing rotor apply radial electromagnetic force by the radial magnetic bearing stator to adjust the radial offset of the rotating shaft, and simultaneously making the radial magnetic bearing rotor apply axial electromagnetic force by the axial magnetic bearing stator to adjust the axial offset of the rotating shaft, and finally achieving the purpose of realizing radial and axial support to the rotating shaft. At the moment, the radial magnetic bearing rotor can be respectively subjected to forces in the radial direction, the lower direction, the left direction and the right direction, which are applied by the radial magnetic bearing stator, and can be subjected to forces in the axial direction, which are applied by the axial magnetic bearing stator, so that the magnetic suspension bearing (the radial magnetic bearing rotor) is formed into a magnetic suspension bearing with 5 degrees of freedom, the use of parts is reduced, the axial size of the rotor is shortened, and the rotor fixed frequency is improved.

Problems with background art 1:

1. the radial magnetic bearing and the axial magnetic bearing are separately arranged, so that the axial magnetic bearing must adopt a thrust bearing (or called axial magnetic bearing rotor) to bear axial electromagnetic force, and the problem of low rotor solid frequency deviation is caused;

2. the detection value of the axial sensor is possibly inconsistent with the actual axial clearance data of the thrust bearing, and the control precision of the system is influenced;

3. the sensors and the axial bearings are arranged separately, so that the number of outlet terminals of the whole system is large; the arrangement of the axial sensor occupies a certain axial space of the main shaft, so that the length of the main shaft is increased, the dynamic performance of the main shaft is reduced, and the cost of the whole system is increased.

Aiming at the problem 1, the invention effectively combines the radial magnetic bearing and the axial magnetic bearing together to form an integrated axial-radial magnetic bearing structure, and compared with the split axial magnetic bearing and the radial magnetic bearing in the prior art, the invention needs to separately arrange a thrust bearing on the axial magnetic bearing to provide axial force for a rotating shaft, and needs to arrange a radial magnetic bearing rotor on the radial magnetic bearing, thereby effectively saving the structure of the thrust bearing, effectively reducing and shortening the axial size of the rotor, and effectively solving the problem of low fixed frequency deviation of the rotor;

in view of the above problem 2, the present invention avoids the above error (i.e. avoids the detection error due to axial expansion) by controlling the flow rate of the cooling fluid according to the shaft elongation to avoid falling into the non-standard temperature range, and determines whether the cooling fluid is in the standard temperature range or the non-standard temperature range by difference;

aiming at the problem 3, the axial displacement sensor is arranged on the axial magnetic bearing, so that the axial displacement sensor and the axial magnetic bearing are combined into a whole, the problem that the number of outlet terminals of the whole system is large due to the fact that the existing sensor and the axial bearing are arranged separately is effectively solved, and the problems that a certain axial space of a main shaft is occupied when the axial sensor is arranged, the length of the main shaft is increased, the dynamic performance of the main shaft is reduced, and the cost of the whole system is increased are solved.

Problems with background art 2:

2. the detection assembly 50' integrated only on the first axial core assembly 30' or the second axial core assembly 40' cannot determine the rotor heating elongation, and a sensor is provided only at one end, so that the rotor heating elongation cannot be effectively detected.

Aiming at the problem 1, the invention effectively combines the radial magnetic bearing and the axial magnetic bearing together to form an integrated shaft-radial integrated magnetic bearing structure, compared with the split axial magnetic bearing and the radial magnetic bearing in the prior art, the invention needs to separately arrange a thrust bearing on the axial magnetic bearing to provide axial force for a shaft, and simultaneously needs to arrange a radial magnetic bearing rotor on the radial magnetic bearing, the structure of the thrust bearing is effectively saved, so that the axial size of the rotor is effectively reduced and shortened, and the problem of low rotor solid frequency deviation is effectively solved;

in view of the above problem 2: the invention adopts the structure that the axial sensors are arranged on both sides of the front axial bearing and the rear axial bearing, the axial extension condition is determined by the axial clearance obtained by calculation through setting the axial extension when the standard temperature interval of the rotor is operated, the extension of the rotor is stabilized in a certain interval through adjusting and increasing or reducing the cooling medium introduced into the magnetic suspension bearing system, the bearing current is reduced, and the operation precision is improved.

The invention improvement point of the invention is as follows:

1. a magnetic suspension bearing system structure with 5 degrees of freedom for double-axial detection. The axial bearings are arranged on two sides of the front radial bearing and the rear radial bearing, so that the use of parts is reduced, the axial size of the rotor is shortened, the fixed frequency of the rotor is improved, and the universality of magnetic suspension bearing parts is improved;

2. a biaxial detection control method. The axial position of the rotor is calculated in a differential mode, and the rotor is judged and adjusted to be positioned at the central position, so that an independent temperature compensation device can be omitted; layout form: write control methods can be considered

3. A method for calculating axial elongation of a motor rotor and a method for controlling flow of a cooling medium are provided. Axial sensor structures are arranged on two sides of the front axial bearing and the rear axial bearing respectively, the axial elongation can be calculated through the axial sensors, and then a cooling medium introduced into the magnetic suspension bearing system is adjusted to enable the elongation of the rotor to be stable in a certain interval, so that the bearing current is reduced, and the running precision of the rotor is improved.

The invention solves the following technical problems:

1. the 5-degree-of-freedom magnetic suspension bearing with the axial bearings arranged on the two sides of the front radial bearing and the rear radial bearing is adopted, a thrust bearing part is omitted, the axial size of the rotor is reduced, and the problem of low solid-phase frequency offset of the rotor is avoided; the magnetic suspension bearing system structure with axial symmetry improves the universality of bearing parts, and avoids the processing of two sets of drawings of front and rear axial parts;

2. the axial sensors are arranged on both sides of the front axial bearing and the rear axial bearing, the oil blocking sleeves are detected on both sides, and the position of the rotor at the axial center position is judged and adjusted in a differential mode, so that the condition that the rotor is axially separated from the center position due to the heating extension of the rotor is avoided (because the axial displacement sensors are arranged on both ends of the rotor, the differential mode is a mode of processing two groups of data detected by the sensors, which mainly means that the 5-freedom-degree magnetic suspension bearing detects the axial deviation of the rotor in the differential mode of double-axial detection and then adjusts the axial position of the rotor through the axial bearing);

3. the axial size change of the rotor is determined by summing the axial distances at the two sides, so that the temperature of the motor rotor can be reversely deduced; the cooling medium introduced into the magnetic suspension bearing system is adjusted and increased or reduced by setting the shaft elongation in the standard temperature range of the operating rotor. (this point mainly indicates that 5 degrees of freedom magnetic bearings can determine the elongation of the rotating shaft through the sum of the axial distances of the two sides, calculate whether the rotor operates in the standard temperature interval, and if the rotor does not operate in the standard temperature interval, the size of a valve of the cooling device in the attached figure 3 can be adjusted, and the flow of the cooling medium can be adjusted, so that the rotor returns to the standard temperature interval.)

Has the advantages that:

1. because the 5-freedom-degree magnetic suspension bearing structure that the axial magnetic bearings are placed on two sides of the front radial bearing and the rear radial bearing is adopted, the use of parts is reduced, the axial size of the rotor is shortened, and the fixed frequency of the rotor is improved;

2. due to the adoption of an axially symmetrical magnetic suspension bearing system structure, the universality of magnetic suspension bearing parts is improved (the magnetic suspension bearings on the two sides of the motor stator are symmetrical relative to the motor stator, and the bearing parts on the left side and the right side can be commonly used);

3. because the axial sensor structures are arranged on both sides of the front axial bearing and the rear axial bearing, under the condition that the rotor generates heat, the axial position of the rotor is calculated in a differential mode, and the rotor is judged and adjusted to be positioned at the central position;

4. the axial sensor structures are arranged on the two sides of the front axial bearing and the rear axial bearing, the axial extension condition is determined by the axial clearance obtained by calculation through setting the axial extension when the rotor operates in a standard temperature interval, the rotor extension is stabilized in a certain interval through adjusting and increasing or reducing a cooling medium introduced into the magnetic suspension bearing system, the bearing current is reduced, and the operation precision is improved.

In some embodiments, the axial magnetic bearing stator 101 includes an axial magnetic bearing core 8 and an axial magnetic bearing coil 4, the axial magnetic bearing core 8 includes a main body portion 80, a first annular portion 81 and a second annular portion 82, the main body portion 80 is a disk structure having a central hole accommodating the rotating shaft 1 therethrough, one end of the first annular portion 81 is connected to the main body portion 80 (preferably, a radially inner end) and the other end extends in a direction of the radial magnetic bearing rotor 6, one end of the second annular portion 82 is connected to the main body portion 80 and the other end extends in a direction of the radial magnetic bearing rotor 6, and the second annular portion 82 is located radially outside the first annular portion 81 to form an accommodating groove 84 between a radially outside of the first annular portion 81 and a radially inside of the second annular portion 82, and the axial magnetic bearing coil 4 is disposed in the accommodating groove 84 and wound around an outer periphery of the first annular portion 81.

The axial magnetic bearing stator is an optimal structure form, and can electrify the axial magnetic bearing coil to generate a magnetic field through the cooperation of the axial magnetic bearing iron core and the axial magnetic bearing coil, so that axial electromagnetic force action is provided for the radial magnetic bearing rotor; the axial magnetic bearing iron core comprises a main body part, a first annular part and a second annular part, so that a containing groove for containing the winding of the axial magnetic bearing coil is formed between the first annular part and the second annular part, structural conditions are provided for arranging the axial magnetic bearing coil, and the axial electromagnetic force can be generated to act on the radial magnetic bearing rotor.

In some embodiments, the first annular portion 81 extends in the axial direction of the rotating shaft 1 and is spaced a first predetermined distance from the radial magnetic bearing rotor 6, and the second annular portion 82 also extends in the axial direction of the rotating shaft 1 and is spaced a second predetermined distance from the radial magnetic bearing rotor 6. The first annular part and the second annular part extend along the axial direction and are arranged at intervals with the radial magnetic bearing rotor, can be opposite to the radial magnetic bearing rotor to provide axial electromagnetic force for the radial magnetic bearing rotor, and are not in contact with the radial magnetic bearing rotor to avoid collision of the radial magnetic bearing rotor and the radial magnetic bearing rotor.

In some embodiments, the radial magnetic bearing 200 further comprises a radial magnetic bearing rotor baffle 5, the radial magnetic bearing rotor baffle 5 is fitted on the rotating shaft 1, and the radial magnetic bearing rotor baffle 5 has two, wherein one radial magnetic bearing rotor baffle 5 is located at one axial end of the radial magnetic bearing rotor 6, and the other radial magnetic bearing rotor baffle 5 is located at the other axial end of the radial magnetic bearing rotor 6; the two radial magnetic bearing rotor baffles 5 are fixedly connected with the radial magnetic bearing rotor 6 and can rotate integrally with the radial magnetic bearing rotor 6. The radial magnetic bearing rotor baffle plate is arranged on the radial magnetic bearing rotor baffle plate, and the radial magnetic bearing rotor baffle plate can limit and position the two axial ends of the radial magnetic bearing rotor and prevent the radial magnetic bearing rotor from moving along the axial direction.

In some embodiments, of the two radial magnetic bearing rotor baffles 5, the radial magnetic bearing rotor baffles 5 that are relatively close to the first and second

annular portions

81, 82 are spaced a third predetermined distance from both the first and second

annular portions

81, 82. According to the invention, the radial magnetic bearing rotor baffle plate between the first annular part and the radial magnetic bearing rotor is arranged to be spaced from the two annular parts by a third preset distance, so that the radial magnetic bearing rotor baffle plate is not contacted with the axial magnetic bearing to prevent collision, and the rotor baffle plate and the radial magnetic bearing rotor can integrally bear the action of axial electromagnetic force of the axial magnetic bearing, thereby improving the action performance of the axial electromagnetic force.

In some embodiments, the radial magnetic bearing stator 201 includes a radial magnetic bearing stator core 7 and a radial magnetic bearing coil 9, and the radial magnetic bearing stator core 7 is also of an annular structure, and is sleeved on the radial periphery of the radial magnetic bearing rotor 6 and spaced from the radial magnetic bearing rotor 6. Preferably, the radial magnetic bearing coil 9 is wound in a direction from one axial end of the radial magnetic bearing stator core 7 to the other axial end thereof. The radial magnetic bearing stator of the present invention includes a radial magnetic bearing stator core and a radial magnetic bearing coil, and is configured to energize the radial magnetic bearing coil to generate a radial magnetic field through the radial magnetic bearing stator core, and further generate a radial electromagnetic force on the radial magnetic bearing rotor, and the radial magnetic bearing stator and the radial magnetic bearing rotor are spaced apart from each other to avoid collision.

In some embodiments, when the axial magnetic bearing stator 101 includes an axial magnetic bearing core 8, the axial magnetic bearing core 8 further includes a third annular portion 83, one end of the third annular portion 83 is connected to the radially outer end of the main body portion 80, and the other end of the third annular portion 83 extends to the radially outer side of the radial magnetic bearing stator core 7 and is connected to the radial magnetic bearing stator core 7. The axial magnetic bearing iron core comprises the third annular part, the third annular part extends to the radial outer side of the radial magnetic bearing stator iron core and is connected with the radial magnetic bearing stator iron core, and the third annular part and the radial magnetic bearing stator iron core are fixed into a whole, so that the integrated structural design of the axial magnetic bearing and the radial magnetic bearing can be realized, the structure is more compact, and a thrust bearing (or called axial magnetic bearing rotor) in the axial magnetic bearing is cancelled.

It is further preferred that the third annular portion extends in the axial direction of the shaft 1.

In some embodiments, the magnetic bearing further comprises a casing 12, the casing 12 is a cylindrical structure and is located at the outer peripheries of the axial magnetic bearing 100 and the radial magnetic bearing 200, one end of the third annular portion 83 is located at one axial side of the radial magnetic bearing 200, and the other end of the third annular portion 83 is located at the other axial side of the radial magnetic bearing 200, such that a partial structure of the third annular portion 83 is located at the outer radial periphery of the radial magnetic bearing stator core 7, the inner radial periphery of the third annular portion 83 is fixedly connected to the radial magnetic bearing stator core 7, and the outer radial periphery of the third annular portion 83 is fixedly connected to the casing 12. The invention also can contain the axial magnetic bearing, the radial magnetic bearing and other structures in the casing, the radial periphery of the third annular part is fixed with the casing, and the radial inner periphery is fixed with the radial magnetic bearing stator core, thus the radial magnetic bearing stator and the axial magnetic bearing are fixed into a whole by utilizing the structural design of the third annular part and are fixed on the casing, the structural integration design is realized, and the structure is more compact.

In some embodiments, the magnetic bearing further comprises an axial displacement sensor 3 and an axial displacement detector 2, the axial displacement sensor 3 is disposed on the axial magnetic bearing 100, the axial displacement detector 2 is disposed on the rotating shaft 1 and can move along with the movement of the rotating shaft 1, and the axial displacement sensor 3 can detect the axial movement of the axial displacement detector 2. The axial displacement sensor and the axial displacement detection piece are designed, so that the axial displacement of the axial displacement detection piece on the displacement rotating shaft can be detected by the axial displacement sensor, and the axial offset degree of the rotating shaft or the expansion and contraction conditions can be effectively detected. The axial displacement sensor is arranged on the axial magnetic bearing, so that the axial displacement sensor and the axial magnetic bearing are combined into a whole, the problem that the number of wire outlet terminals of the whole system is large due to the fact that the conventional sensor and the axial bearing are arranged separately is effectively solved, and the problems that the length of a main shaft is increased, the dynamic performance of the main shaft is reduced and the cost of the whole system is increased due to the fact that the axial sensor needs to occupy a certain axial space of the main shaft when being arranged are also solved.

In some embodiments, when the axial magnetic bearing stator 101 includes an axial magnetic bearing core 8, the axial displacement sensor 3 is of an annular structure and is fixedly disposed on the axial magnetic bearing core 8, the axial displacement detector 2 is also of an annular structure and is fixedly disposed on the rotating shaft 1, and the axial displacement detector 2 can also perform an oil-blocking function on the axial magnetic bearing 100 and the radial magnetic bearing 200. The axial displacement sensor and the axial displacement detecting element are both of annular structures, and the axial displacement detecting element can be matched with the axial displacement sensor to detect the axial deviation or thermal expansion condition of the rotating shaft, and can also play a role in resisting oil for the axial magnetic bearing and the radial magnetic bearing, namely a role in resisting oil.

In some embodiments, the magnetic bearing assembly comprises at least two of the axial magnetic bearing 100, the radial magnetic bearing 200, the axial displacement sensor 3 and the axial displacement detector 2, and one of the magnetic bearing assemblies is disposed on one axial side of the motor assembly, the other magnetic bearing assembly is disposed on the other axial side of the motor assembly, and the two magnetic bearing assemblies are symmetrically disposed with respect to the motor assembly. The invention also improves the universality of bearing parts and avoids the processing of two sets of drawings of front and rear axial parts by at least two magnetic bearing components, wherein one magnetic bearing component is arranged at one axial side of the motor component, the other magnetic bearing component is arranged at the other axial side of the motor component, and the two magnetic bearing components are symmetrically arranged relative to the motor component; and because the axial sensor structures are arranged on the two sides of the front axial bearing and the rear axial bearing, under the condition that the rotor generates heat, the axial position of the rotor is calculated in a differential mode, the rotor is judged and adjusted to be positioned at the central position, the condition that the rotor is axially separated from the central position due to the heating extension of the rotor is avoided, the heating extension amount of the rotor can be effectively detected, and the problem that the heating extension amount cannot be detected and determined in the prior art is solved.

The invention provides a 5-degree-of-freedom magnetic suspension bearing system for biaxial detection, which comprises a rotating shaft 1, an axial displacement detector 2, an axial displacement sensor 3, an axial magnetic bearing coil 4, a radial magnetic bearing rotor baffle 5, a radial magnetic bearing rotor 6 (preferably a silicon steel sheet), a radial magnetic bearing stator iron core 7, an axial magnetic bearing iron core 8, a radial magnetic bearing coil 9, a motor rotor 10, a motor stator 11, a machine shell 12 and a cooling device 13, as shown in figure 3.

As shown in FIG. 3, the front and rear radial bearings, the front and rear axial bearings and the front and rear displacement sensors are completely symmetrical, so that the universality of the magnetic suspension bearing part is improved.

In some embodiments, the motor assembly includes a motor rotor 10 and a motor stator 11. This is a preferred form of construction of the motor assembly of the invention.

In some embodiments, a cooling device 13 is further included, and the cooling device 13 is capable of introducing a cooling fluid to cool the rotating shaft 1, the axial magnetic bearing 100 and the radial magnetic bearing 200 according to the axial movement data of the axial displacement detector 2 detected by the axial displacement sensor 3. It is further preferred that the cooling means is arranged on the housing 12. The cooling device can cool the rotating shaft in a non-standard temperature range, so that the condition of inaccurate detection precision caused by thermal expansion is effectively avoided; the invention adopts the structure that the axial sensors are arranged on both sides of the front and the rear axial bearings, the shaft elongation is determined by the axial clearance obtained by calculation through setting the shaft elongation in the standard temperature interval of the operating rotor, the rotor elongation is stabilized in a certain interval through adjusting and increasing or reducing the cooling medium introduced into the magnetic suspension bearing system, the bearing current is reduced, and the operating precision is improved. The invention avoids the flow of the cooling fluid from falling into the nonstandard temperature interval by controlling the flow of the cooling fluid according to the axial elongation, thereby avoiding the error (namely avoiding the detection error caused by axial expansion), judges whether the cooling fluid is in the standard temperature interval or the nonstandard temperature interval by difference, can effectively detect the heating elongation of the rotor, and solves the problem that the detection value of the axial sensor is possibly inconsistent with the actual axial clearance data of the thrust bearing, which can influence the control precision of the system.

The present invention also provides a method for controlling a magnetic bearing system as described in any one of the preceding items, as shown in fig. 5, wherein: when the axial magnetic bearing stator 101 comprises an axial magnetic bearing core 8 and axial magnetic bearing coils 4, and when the magnetic bearing system further comprises a cooling device 13:

the control method comprises the following steps:

detecting, namely detecting the axial deviation condition of the rotating shaft 1 through an axial displacement sensor 3 on one axial side of the motor assembly, and simultaneously detecting the axial deviation condition of the rotating shaft 1 through an axial displacement sensor 3 on the other axial side of the motor assembly;

a control step of controlling the energizing current of an axial magnetic bearing coil 4 of the axial magnetic bearing to change to adjust the axial deviation of the rotating shaft when the rotating shaft operates in a standard temperature interval, and turning off the cooling device at the moment; when the rotating shaft operates in a non-standard temperature interval, controlling the cooling device to be opened to cool the rotating shaft, simultaneously controlling an axial magnetic bearing coil 4 of the axial magnetic bearing to operate, and controlling the energizing current of the axial magnetic bearing coil 4 to be changed or unchanged;

the standard temperature interval is a temperature interval in which the deformation of the rotating shaft caused by thermal expansion and cold contraction does not occur, and the nonstandard temperature interval is a temperature interval in which the deformation of the rotating shaft caused by thermal expansion and cold contraction occurs.

According to the invention, the axial sensor structures are arranged on both sides of the front axial bearing and the rear axial bearing, the axial deviation condition of the rotating shaft 1 is detected, the shaft extension condition is obtained, whether the shaft extension condition is in a standard temperature interval or in a non-standard temperature interval is judged, and the rotor returns to the standard temperature interval in the non-standard temperature interval by adjusting, increasing or reducing the cooling medium introduced into the magnetic suspension bearing system, so that the extension amount is stabilized in a certain interval, the use of the bearing current can be effectively reduced, the condition of inaccurate axial deviation detection precision caused by thermal expansion and cold contraction is avoided, and the detection precision and the operation precision of the axial deviation are effectively improved.

In some embodiments, in the detecting step, a first gap between the axial displacement detecting member and the corresponding axial displacement detecting member is detected by the axial displacement sensor 3 on one axial side of the motor assembly, and a second gap between the axial displacement detecting member and the corresponding axial displacement detecting member is detected by the axial displacement sensor 3 on the other axial side of the motor assembly;

when the first gap is decreased and the second gap is increased, and the decrease amount of the first gap and the increase amount of the second gap are not within an error range; or, when the first gap is increased and the second gap is decreased, and the amount of increase of the first gap and the amount of decrease of the second gap are not within an error range; or when the first gap and the second gap decrease or increase simultaneously; judging that the rotating shaft operates in a non-standard temperature range;

in the control step, when the rotating shaft operates in a standard temperature interval, the energizing current of an axial magnetic bearing coil 4 of the axial magnetic bearing is controlled to change to adjust the first gap and the second gap, and at the moment, the cooling device is closed; when the rotating shaft operates in a non-standard temperature interval, controlling the cooling device to be opened to cool the rotating shaft, simultaneously controlling an axial magnetic bearing coil 4 of the axial magnetic bearing to operate, and controlling the energizing current of the axial magnetic bearing coil 4 to be changed or unchanged; and controlling the increase or decrease of the cooling flow rate of the cooling device according to the first gap and the second gap.

The method is a preferred control form of the invention, namely, a differential comparison method is explained, and the method can effectively judge whether the rotating shaft is in a standard temperature interval or a non-standard temperature interval; when the first gap is decreased and the second gap is increased, and the decrease amount of the first gap and the increase amount of the second gap are within an error range; or, when the first gap is increased and the second gap is decreased, and the amount of increase of the first gap and the amount of decrease of the second gap are within an error range; judging that the rotating shaft operates in a standard temperature range;

when the first gap is decreased and the second gap is increased, and the decrease amount of the first gap and the increase amount of the second gap are not within an error range; or, when the first gap is increased and the second gap is decreased, and the amount of increase of the first gap and the amount of decrease of the second gap are not within an error range; or when the first gap and the second gap decrease or increase simultaneously; and judging that the rotating shaft operates in a non-standard temperature range.

The invention carries out differential comparison by detecting the deviation degree of the two ends of the rotating shaft, thereby judging whether the rotating shaft operates in a standard temperature interval or a non-standard temperature interval, if the rotating shaft does not deform due to expansion with heat and contraction with cold under the standard temperature interval, the axial deviation of the rotating shaft can be adjusted only by adjusting the size of the electrified current, if the rotating shaft deforms due to expansion with heat and contraction with cold under the non-standard temperature interval, cooling fluid is firstly introduced to cool the rotating shaft and the like, the temperature returns to the standard temperature interval, the condition of low detection precision caused by the deformation due to expansion with heat and contraction with cold is effectively avoided, and the use of the bearing current is reduced.

The operating principle of the invention is preferably as follows:

axial displacement sensors in the magnetic suspension bearing system are arranged at two ends of a rotating shaft and are responsible for detecting axial displacement of an axial displacement detection piece 2 (preferably an axial displacement detection ring), when the system normally operates in a standard temperature range, the rotating shaft 1 has a certain elongation, and a set gap between the axial displacement sensors and the axial displacement detection rings at two ends is determined by combining the elongation;

when the rotating shaft operates in a standard temperature range, but the rotating shaft 1 has axial displacement towards the front end, the gap between the front end axial detection ring and the front end axial displacement sensor is increased, the gap between the rear end axial detection ring and the rear end axial displacement sensor is reduced, the axial displacement sensors at the two ends transmit the axial displacement data detected at the moment to the system controller, and the system controller adjusts the axial position of the main shaft by reducing the input current of the front end axial bearing and increasing the input current of the rear end axial bearing; (As can be understood from FIG. 3 of the drawings, there are axial bearing coils at both ends, and where the current is large and the rotating shaft 1 is offset, the gap between the corresponding axial direction detecting member 2 and the axial direction sensor 3 is also increased).

When the rotating shaft operates in a standard temperature range, but the rotating shaft 1 axially displaces towards the rear end, the gap between the front end axial detection ring and the front end axial displacement sensor is reduced, the gap between the rear end axial detection ring and the rear end axial displacement sensor is increased, the axial displacement sensors at the two ends transmit the detected axial displacement data to the system controller, and the system controller adjusts the axial position of the main shaft by increasing the input current of the front end axial bearing and reducing the input current of the rear end axial bearing so as to return the rotating shaft to the original position as far as possible;

when the rotating shaft operates in a non-standard temperature interval, the rotor is extended or shortened, the set gaps between the front and rear end axial detection rings and the front and rear end axial displacement sensors are increased or decreased (namely, the rotor deforms due to thermal expansion or cold contraction), the axial displacement sensors at the two ends transmit the detected axial displacement data to the system controller, the system controller analyzes the obtained displacement data, outputs a control signal, adjusts the flow of a cooling medium introduced into the magnetic suspension bearing system to enable the extension amount of the rotor to be stable in a certain interval, reduces the bearing current (namely, reduces the use of the current for adjusting the offset of the rotating shaft), and improves the operation precision;

the magnetic suspension system for double-axial detection improves the universality of magnetic suspension bearing parts because the bearings at the front end and the rear end are axially symmetrical; the method comprises the steps of analyzing according to the measured data of front and rear end axial displacement sensors, not only adjusting the input current of front and rear axial bearings to adjust the axial position of a spindle, but also analyzing whether a motor rotor operates in a standard temperature interval or not according to the input current, and then adjusting the flow of a cooling medium introduced into a magnetic suspension bearing system to stabilize the elongation of the rotor in a certain interval, so as to reduce the bearing current (the term of reducing the bearing current refers to the fact that the axial length of the rotor can be controlled through the use of the cooling medium, so that the use of the bearing current in a non-standard temperature interval is reduced), improve the operation precision, prevent axial collision and improve the operation stability of the magnetic suspension system.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention. The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims

1. A magnetic bearing system, characterized by: the method comprises the following steps:

the magnetic bearing comprises a rotating shaft (1), an axial magnetic bearing (100) and a radial magnetic bearing (200), wherein the axial magnetic bearing (100) and the radial magnetic bearing (200) are sleeved on the periphery of the rotating shaft (1), the axial magnetic bearing (100) comprises an axial magnetic bearing stator (101), the radial magnetic bearing (200) comprises a radial magnetic bearing stator (201) and a radial magnetic bearing rotor (6), the radial magnetic bearing rotor (6) is sleeved on the periphery of the rotating shaft (1) and can rotate along with the rotating shaft (1), the radial magnetic bearing stator (201) is positioned on the periphery of the radial magnetic bearing rotor (6) and can apply radial electromagnetic force to the radial magnetic bearing rotor (6), at least part of the structure of the axial magnetic bearing stator (101) in the axial direction of the rotating shaft (1) is positioned at one axial end of the magnetic bearing rotor (6), and the axial magnetic bearing stator (101) can apply axial electromagnetic force to the radial magnetic bearing rotor (6).

2. The magnetic bearing system of claim 1, wherein:

the axial magnetic bearing stator (101) includes an axial magnetic bearing core (8) and an axial magnetic bearing coil (4), the axial magnetic bearing core (8) includes a main body portion (80), a first annular portion (81) and a second annular portion (82), the main body portion (80) is a disk structure having a central hole, the central hole accommodates the rotating shaft (1) therethrough, one end of the first annular portion (81) is connected to the main body portion (80) and the other end extends in a direction of the radial magnetic bearing rotor (6), one end of the second annular portion (82) is connected to the main body portion (80) and the other end extends in a direction of the magnetic bearing radial rotor (6), and the second annular portion (82) is located at a radially outer side of the first annular portion (81) to form an accommodating groove (84) between the radially outer side of the first annular portion (81) and the radially inner side of the second annular portion (82), the axial magnetic bearing coil (4) is disposed in the accommodating groove (84) and wound around an outer periphery of the first annular portion (81).

3. The magnetic bearing system of claim 2, wherein:

the first annular portion (81) extends in the axial direction of the rotary shaft (1) and is spaced apart from the radial magnetic bearing rotor (6) by a first predetermined distance, and the second annular portion (82) also extends in the axial direction of the rotary shaft (1) and is spaced apart from the radial magnetic bearing rotor (6) by a second predetermined distance.

4. The magnetic bearing system of claim 2, wherein:

the radial magnetic bearing (200) further comprises two radial magnetic bearing rotor baffles (5), the radial magnetic bearing rotor baffles (5) are sleeved on the rotating shaft (1), one radial magnetic bearing rotor baffle (5) is positioned at one axial end of the radial magnetic bearing rotor (6), and the other radial magnetic bearing rotor baffle (5) is positioned at the other axial end of the radial magnetic bearing rotor (6); the two radial magnetic bearing rotor baffles (5) are fixedly connected with the radial magnetic bearing rotor (6) and can integrally rotate along with the radial magnetic bearing rotor (6).

5. The magnetic bearing system of claim 4, wherein:

of the two radial magnetic bearing rotor baffles (5), the radial magnetic bearing rotor baffle (5) relatively close to the first annular portion (81) and the second annular portion (82) is spaced from both the first annular portion (81) and the second annular portion (82) by a third predetermined distance.

6. Magnetic bearing system according to any of claims 1 to 5, characterized in that:

the radial magnetic bearing stator (201) comprises a radial magnetic bearing stator core (7) and a radial magnetic bearing coil (9), wherein the radial magnetic bearing stator core (7) is also of an annular structure, is sleeved on the radial periphery of the radial magnetic bearing rotor (6) and is arranged at intervals with the radial magnetic bearing rotor (6).

7. The magnetic bearing system of claim 6, wherein:

when the axial magnetic bearing stator (101) comprises an axial magnetic bearing iron core (8), and the axial magnetic bearing iron core (8) comprises a main body part (80), the axial magnetic bearing iron core (8) further comprises a third annular part (83), one end of the third annular part (83) is connected with the radial outer side end of the main body part (80), and the other end of the third annular part (83) extends to the radial outer side of the radial magnetic bearing stator iron core (7) and is connected with the radial magnetic bearing stator iron core (7).

8. The magnetic bearing system of claim 7, wherein:

the magnetic bearing further comprises a machine shell (12), the machine shell (12) is of a cylindrical structure and is located on the peripheries of the axial magnetic bearing (100) and the radial magnetic bearing (200), one end of the third annular part (83) is located on one axial side of the radial magnetic bearing (200), the other end of the third annular part (83) is located on the other axial side of the radial magnetic bearing (200), so that part of the structure of the third annular part (83) is located on the radial periphery of the radial magnetic bearing stator core (7), the radial inner periphery of the third annular part (83) is fixedly connected with the radial magnetic bearing stator core (7), and the radial outer periphery of the third annular part (83) is fixedly connected with the machine shell (12).

9. Magnetic bearing system according to any of claims 1 to 8, characterized in that:

the axial displacement sensor (3) is arranged on the axial magnetic bearing (100), the axial displacement detection piece (2) is arranged on the rotating shaft (1) and can move along with the movement of the rotating shaft (1), and the axial displacement sensor (3) can detect the axial movement of the axial displacement detection piece (2).

10. The magnetic bearing system of claim 9, wherein:

when the axial magnetic bearing stator (101) comprises an axial magnetic bearing iron core (8), the axial displacement sensor (3) is of an annular structure and is fixedly arranged on the axial magnetic bearing iron core (8), the axial displacement detection piece (2) is also of an annular structure and is fixedly sleeved on the rotating shaft (1), and the axial displacement detection piece (2) can also perform oil resistance on the axial magnetic bearing (100) and the radial magnetic bearing (200).

11. The magnetic bearing system of claim 9, wherein:

the magnetic bearing assembly comprises at least two axial magnetic bearings (100), at least two radial magnetic bearings (200), at least two axial displacement sensors (3) and at least two axial displacement detection pieces (2), wherein one magnetic bearing assembly is arranged on one axial side of the motor assembly, the other magnetic bearing assembly is arranged on the other axial side of the motor assembly, and the two magnetic bearing assemblies are symmetrically arranged relative to the motor assembly.

12. The magnetic bearing system of claim 11, wherein:

the motor assembly comprises a motor rotor (10) and a motor stator (11).

13. The magnetic bearing system of claim 11, wherein:

the axial displacement sensor (3) is used for detecting axial movement data of the axial displacement detection piece (2), and the cooling device (13) can introduce cooling fluid to cool the rotating shaft (1), the axial magnetic bearing (100) and the radial magnetic bearing (200) according to the axial movement data of the axial displacement detection piece (2).

14. A method of controlling a magnetic bearing system according to any of claims 11 to 13, wherein: when the axial magnetic bearing stator (101) comprises an axial magnetic bearing core (8) and axial magnetic bearing coils (4), and when the magnetic bearing system further comprises a cooling device (13):

the control method comprises the following steps:

detecting, namely detecting the axial deviation condition of the rotating shaft (1) through an axial displacement sensor (3) on one axial side of the motor component, and simultaneously detecting the axial deviation condition of the rotating shaft (1) through an axial displacement sensor (3) on the other axial side of the motor component;

a control step, when the rotating shaft operates in a standard temperature interval, controlling the electrified current of an axial magnetic bearing coil (4) of the axial magnetic bearing to change so as to adjust the axial deviation of the rotating shaft, and closing the cooling device at the moment; when the rotating shaft operates in a non-standard temperature interval, controlling the cooling device to be opened so as to cool the rotating shaft, simultaneously controlling an axial magnetic bearing coil (4) of the axial magnetic bearing to operate, and controlling the energizing current of the axial magnetic bearing coil (4) to be changed or not changed;

15. The control method according to claim 14, characterized in that:

in the detection step, a first gap between the axial displacement detection piece and the corresponding axial displacement detection piece is detected through the axial displacement sensor (3) on one axial side of the motor assembly, and a second gap between the axial displacement detection piece and the corresponding axial displacement detection piece is detected through the axial displacement sensor (3) on the other axial side of the motor assembly;

in the control step, when the rotating shaft operates in a standard temperature interval, the energizing current of an axial magnetic bearing coil (4) of the axial magnetic bearing is controlled to change to adjust the first gap and the second gap, and the cooling device is closed at the moment; when the rotating shaft operates in a non-standard temperature interval, controlling the cooling device to be opened to cool the rotating shaft, simultaneously controlling an axial magnetic bearing coil (4) of the axial magnetic bearing to operate, and controlling the energizing current of the axial magnetic bearing coil (4) to be changed or unchanged; and controlling the increase or decrease of the cooling flow rate of the cooling device according to the first gap and the second gap.